Hybrid modules are used in many vehicles in various constructions. In some applications, the hybrid modules are connected to an internal combustion engine or combustion engine on an input side and to a shiftable transmission and further components of the powertrain on their output side. Rotational irregularities or unwanted vibrations can also be injected or coupled into the hybrid module via the internal combustion engine during transmission of a driving torque. A torque component that can lead to the unwanted vibrations or rotational irregularities may possibly also be attributable to an ignition behavior and/or a speed or operating condition of the internal combustion engine.
In many cases, the hybrid module comprises a vibration reducing system for reducing the unwanted vibrations in the hybrid module or powertrain. Accordingly, the vibration reducing system is intended to help homogenize an alternating torque resulting from a combustion engine or the internal combustion engine so that it does not lead to vibrations or noise excitation in the hybrid module, the powertrain or other components of a vehicle in which the hybrid module is installed. Unwanted vibrations can also be caused or promoted by other factors, for example, a roadway surface or subsurface over which the vehicle moves.
Therefore, conventional vibration reducing systems are mostly configured such that they can reduce vibrations occurring in all operating conditions of the combustion engine or driving conditions of the vehicle. As a result, conventional vibration reducing systems generally have a multistage vibration reducing system characteristic or spring characteristic with a knee. Conventional vibration reducing systems can be constructed, for example, as a two-mass flywheel, power split or converter combined with a torsion damper, a turbo torsion damper and/or a two-damper converter. In some cases, the aforementioned dampers are also combined with a speed adaptive mass damper. Vibration reducing systems of this kind are also known as passive vibration reducing systems.
In some hybrid modules, these passive vibration reducing systems can be combined with an electric machine for active vibration reduction or as active vibration reducing system. For example, DE 197 48 665 A1 discloses a device for vibration isolation in a powertrain of a motor vehicle. In this case, an electric machine is arranged as vibration reducing system in the powertrain upstream of a vibration isolation device. By means of the electric machine, torques are applied to the input shaft and to the output shaft, respectively, in such a way that the vibration isolation device has an increased or reduced effective spring stiffness.
Therefore, there is a need to find a better compromise between improved vibration reduction in a hybrid module and a simple construction of the hybrid module.